Background Landfilling of waste commenced in 1994 in North Kerry Landfill, the first engineered landfill site in Ireland. Furthermore, it was the first landfill site in Ireland to be managed under an EPA Waste Licence (W0001). It accepted non-hazardous waste including a percentage of biodegradable material. A flare was operated on site to manage the landfill gas being abstracted from the gas wells. Methane, carbon dioxide, and oxygen were also produced during the waste decomposition. Gas wells were drilled down into the waste body and connected to a flare system, which burned the gas at over 1,000°C. Solution In the early 2000s, Kerry County Council identified that, in order to mitigate against any fugitive emissions and odours from the site, and to utilise the gas produced as an energy resource where feasible, it was necessary to introduce a well-managed gas utilisation plant to the site (Figure1.0). The overall objective of a landfill gas management system was to collect all gas produced from the waste and treat it in a manner so as to minimise odours and emissions from the landfill and to provide energy recovery where feasible. It was the intention of Kerry County Council to use the landfill electricity generation process to realise the financial value of the landfill gas while at the same time meeting EPA requirements. The gas utilisation plant was identified along with the flare as the key gas infrastructure to: minimise the impact on air quality and the effect of greenhouse gases on the climate; minimise the risk of migration of landfill gas beyond the perimeter of the site minimise the risk of migration of landfill gas into services and buildings on site; avoid unnecessary ingress of air into the landfill and thereby minimise the risk of landfill fires; minimise the damage to soils and vegetation within the restored landfill area; permit effective control of gas emissions; and, where practicable, permit energy recovery. Kerry County Council also highlighted the need to engage landfill gas experts to manage the gas production and utilisation in order to adhere to EPA Waste Licence conditions. The contractor was responsible for constructing the generation facility and for the installation, operation, and maintenance of the electricity generation equipment to utilise the landfill gas from the landfill site to generate electricity. Benefits of solution Environmental According to the EPA Landfill Manuals, “[m]ethane is estimated to be 20 – 30 times more damaging (per molecule) than carbon dioxide to the global climate due to its greenhouse effect”. 8 With the conversion of gas to electricity and flaring of landfill gas produced to over 1,000°C, there have been very little fugitive emissions from the North Kerry Landfill site. This has been confirmed through volatile organic compound questionnaires in accordance with the EPA Air Guidance Note 5. Over the years, the gas utilisation plant has been operating at full capacity (330kW) 80-90% of the time. Since 2018, there has been a reduction in gas produced but there have been no environmental impacts as a result of this reduction. Economic The landfill gas generated on site yields a monthly royalty payment to Kerry County Council. This is calculated based on the electricity produced from the landfill gas intake, and the actual and base energy prices. Between 2011 and 2018, the average amount of electricity produced was approximately 1.6MWh per annum. Social The number of public complaints regarding the landfill reduced considerably between 2012 and 2018. With the introduction of a gas utilisation plant to a landfill site, landfill gas management is better managed with a key focus on any fugitive emission from site. Even though the site is located away from residential properties, odour management is one of Kerry County Council’s key priorities. Since the closure of North Kerry Landfill to the public, there have been no odour complaints. Figure 1.0: Kerry gas utilisation plant.